The present invention relates to fabric for reinforcing concrete, as for example concrete pipe and the like. It is particularly related to fabric in which stirrups are used as additional reinforcement.
Stirrups comprise projections, usually of wire rod, out of the general plane of the fabric itself. Where the fabric is laid flat, the stirrups project generally upwardly or downwardly therefrom and provide additional reinforcement when the concrete is cast therearound. When the fabric is rolled into cages for reinforcing pipe, the stirrups project generally radially outwardly or inwardly from the cage with respect to the center of the pipe. Typically, the projections are secured to the fabric just prior to casting concrete therearound. The individual stirrups are usually welded to the fabric. Generally sinusoidal shaped stirrup segments are also available which can be welded at several spaced points along the length thereof to the fabric, thereby eliminating the need to weld each and every projection to the fabric.
In order to obviate the necessity of welding stirrups to the fabric on the job site, I have invented a fabric in which stirrup means are hingedly joined to the fabric. In this manner, the fabric can be shipped with the stirrup members already joined thereto, lying generally flat, generally in the plane of the fabric. On the job site, the stirrups can be rotated into an erect position. This invention is disclosed and claimed in my U.S. Pat. No. 3,840,054 issued Oct. 8, 1974. "STIRRUP FABRIC AND METHOD FOR FORMING PIPE REINFORCEMENT" and is assigned to the assignee of the present invention. While this invention is a tremendous advance over the prior art described above, it does suffer a drawback in that the hinges used to join the stirrups to the fabric constitute a cost factor which must be included in the price of the fabric. Further, the installation of the hinges is a cost factor the elimination of which would be desirable.